Q 59
LOAN WORKS.
ABERDEEN VALLEY WATER SCHEME.
227. Preliminary Works:-Further surveys of the Lower Reservoir were made in connection with the removal of silt.
228. East Catchwater, Second Section:-This work was completed in 1933, the maintenance period expiring on 26th April, 1934, when the retention money was paid to the Contractors, Messrs. Blackmore & Blackburn.
229. West Catchwater, Second Section:-This work was completed satisfactorily in the extended contract time on 28th February, and the retention money was paid at the termination of the maintenance period which expired on the 28th August. This section, which drains an area of 179 acres of the southern slopes of Mount Kellett and discharges the run off into the first section of the West Catchwater, consists of two portions, the first or lower one being 3,021 feet in length at a level of approximately 390.00 A.O.D. whilst the second portion at an approximate level of 750.00 A.O.D. is 3,942 feet in length, the two portions being connected by a stepped section 566 feet long. A run off of 2/3" of rain per hour is collected by this catchwater, overflows being provided to discharge any excess rainfall up to a rate of 3⅓" per hour. The catchwater has been constructed in four different sizes varying from an effective cross-sectional area of 22.50 square feet at the outfall to 6.5 square feet at the intake. The invert and lower part of the sidewalls were constructed of 1:2:4 cement concrete 3″ thick on the smaller sections and 4½″ in the larger sections whilst the remainder of the sidewalls were constructed of 1:4:8 cement concrete of thicknesses similar to those of the invert. The side slopes are 2 to 1 in soft section and ½ to 1 in rock section. Along the outside of the catchwater a path of minimum width of 3' 0" has been formed and this was carried over the overflows on reinforced concrete decking. Sand-traps, each having a washout pipe, have been constructed in the invert at all overflows. The step down section connecting the upper and lower portions has been lined and stepped where necessary.
After construction work was completed heavy rainstorms on June 21st to 23rd caused several earth slips and damage to the catchwater. Repairs were carried out and charged against Typhoon and Rainstorm Damages.
230. Alterations to Lower Dam, Removal of Silt:-The contract for extending this work which was referred to in paragraph 244 of last year's Report was let to The Union Construction Co. on 27th January for $19,730.00. Work was commenced on 1st February and was completed on 30th June. The amount of silt removed was 44,048 cubic yards making a grand total of 129,032 cubic yards. The storage capacity of the Reservoir has thus been increased to 106.89 million gallons. The maintenance period expired on 30th November and the retention money was released.
Q 59
LOAN WORKS.
ABERDEEN VALLEY WATER SCHEME.
227. Preliminary Works:-Further surveys of the Lower Reservoir were made in connection with the removal of silt.
228-East Catchwater, Second Section:-This work was completed in 1933, the maintenance period expiring on 26th April, 1934, when the retention money was paid to the Con- tractors, Messrs. Blackmore & Blackburn.
229. West Catchwater, Second Section:-This work was completed satisfactorily in the extended contract time on 28th February, and the retention money was paid at the termination of the maintenance period which expired on the 28th August. This section, which drains an area of 179 acres of the southern slopes of Mount Kellett and discharges the run off into the first section of the West Catchwater, consists of two portions, the first or lower one being 3,021 feet in length at a level of approximately 390.00 A.O.D. whilst the second portion at an approximate level of 750.00 A.O.D. is 3,942 feet in length, the two portions being connected by a stepped section 566 feet long. A run off of 2/3" of rain per hour is collected by this catch- water, overflows being provided to discharge any excess rainfall up to a rate of 33" per hour. The catchwater has been con- structed in four different sizes varying from an effective cross- sectional area of 22.50 square feet at the outfall to 6.5 square feet at the intake. The invert and lower part of the sidewalls were constructed of 1.2.4. cement concrete 3′′ thick on the smaller sections and 41" in the larger sections whilst the re- mainder of the sidewalls were constructed of 1.4.8 cement con- crete of thicknesses similar to those of the invert. The side slopes are 2 to 1 in soft section and 8 to 1 in rock section. Along the outside of the catchwater a path of minimum width of 3' 0" has been formed and this was carried over the overflows on reinforced concrete decking. Sand-traps, each having a washout pipe, have been constructed in the invert at all over- flows. The step down section connecting the upper and lower portions has been lined and stepped where necessary.
After construction work was completed heavy rainstorms on June 21st to 23rd caused several earth slips and damage to the catchwater. Repairs were carried out and charged against Typhoon and Rainstorm Damages.
230. Alterations to Lower Dam, Removal of Silt:-The contract for extending this work which was referred to in paragraph 244 of last year's Report was let to The Union Construction Co. on 27th January for $19,730.00. Work was commenced on 1st February and was completed on 30th June. The amount of silt removed was 44,048 cubic yards making a grand total of 129,032 cubic yards. The storage capacity of the Reservoir has thus been increased to 106.89 million gallons. The maintenance period expired on 30th November and the re- tention money was released.
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